As a weather strip fitted to a body flange 3 on a periphery of body opening sections 2 and 2a of a motor vehicle 1 as is seen in FIG. 1, a weather strip 4 as is seen in FIG. 2 is used on occasions. This weather strip 4 is of a type coupling a fitting base section (welt) 5 integrally with a hollow section (strip) 6. The fitting base section 5 sandwiches a body flange 3. The hollow section 6 has a cross section shaped approximately into numeral 8, and is constituted of a abutting section 7 which is formed with a seal hollow chamber 7a, and a middle section 8 which is integrated with the abutting section 7 and is provided with a hollow chamber 8a. 
The fitting base section 5 has a core material 9, and is shaped approximately into U. The fitting base section 5 has an internal surface which is formed with flange-sandwiching lips 10, and an external surface which is formed with an ornament lip 11. The hollow section 6 is made of a comparatively soft elastic body such as a sponge rubber, a soft thermoplastic elastomer or the like. The fitting base section 5 is made of a comparatively hard material such as a solid rubber, a hard thermoplastic elastomer or the like. When the weather strip 4 is fitted to the body flange 3, the flange-sandwiching lips 10 sandwich a flange. Under the fitting condition, the ornament lip 11 is a section that contacts a garnish.
However, according to the weather strip 4 as described above, deflection of the hollow section 6 in fitting sections indicated by A to I of the body opening sections 2 and 2a varies with an input direction F (F1, F2, F3 and F4) of a seal surface 12a of a door panel 12, as is seen in FIG. 3 and FIG. 4.
Namely, as is seen in FIG. 3, in fitting sections C, G, A, E, B and F, the input (F1, F2 and F3) is applied in such a manner as to push the hollow section 6 toward an outside of the periphery of the body opening sections 2 and 2a. On the other hand, as is seen in FIG. 4, in a fitting section D on a front side of a center pillar 1a, in a fitting section I on a front side of a rear pillar 1b, and in a fitting section H below the rear pillar 1b, the input (F4) is applied in such a manner as to push the hollow section 6 toward the fitting base section 5.
Thereby, in view of an entire circumference of the body opening sections 2 and 2a, the hollow section 6 is twisted and thereby is not constant in shape (of deflection), especially, in an area where the fitting sections D, I and H change to other sections. Thereby, failures occur such as lines so generated as to increase wind noise, water tightness decreased, and external appearance deteriorated. Above all, the above phenomena notably appear at an upper corner on the front side of the center pillar 1a of the body opening section 2.
Whereupon, in view of the above circumstances, the present invention provides such a weather strip as to allow the hollow section 6 to assume an approximately the same shape (of deflection) in each section, irrespective of the input direction of the seal surface 12a when the door panel 12 is closed.